Best 300B tube for Cayin 300B amp?

oceanica...i just replaced my previous sophia 'princess' with the new sophia 'royal princess' and it is much-much better. read the new review on positive feedback magazines website by jeff day...it really is great.i have about 20 hrs on them and they keep improving but right out of the box were significantly better...soundstage..bass ..mids ..everything...

Calloway, what amplifier(s) are you using with them? Since the OP stated their amplifier of choice for usage in. I recently bought a barely used matched quad set of "royal princess" for use in my Wavelength Cardinal XS amplifier pair.
Oceanica, My amplifiers are too recent to me to have tried different tube pairings, tho, I earlier purchased a pair of Shuguang Black Treasures. I have no complaints with either, but have been too busy enjoying the music to exchange for an attempt at a comparison. I suppose this was not much help:) Interested in your future findings.

Clarification: Wavelength Cardinal uses one single 300B per mono amplifier. Pair in use and back-up pair. Nice:)